Information for users from the old Q&A site
If you have an account from our old Q&A site, your account was transferred over, but you need to reset your password and confirm your email address.
Reset Password here
Confirm Email here

I have a lot of trouble telling the difference between augite and hornblende. I have read everywhere that a good way to tell is to look at the angle of cleavage- augite has about 90 degree angles and hornblende has about 60 or 120 degree angles, but this doesn't seem to work for me! All of the angles look like they are 90 degrees, or there aren't any cleavage planes as far as I can tell. I have also read that augite has octagonal or rectangular cross sections, while hornblende has diamond shaped cross sections. If any of these techniques work, please let me know how to be sure you're identifying it right each time, or tell me if you have another surefire way to identify augite vs hornblende!

2 Answers

0 votes

These two minerals can be very difficult to distinguish visually if their crystals don't form visible angles that can be measured. Usually locality can be a determination, but in rougher samples where the crystals are non-discernible this can be very difficult to distinguish.